The invention relates to a radio sensor comprising a support and a transceiver aerial, for realising with polar co-ordinates a radio map of a site, after a detection of a duration TM.
The invention can be used for civil as well as military purposes. When attached to an aircraft, such a radio sensor can be used at low altitude for forming a picture of the nearby landscape situated ahead of the aircraft. The same sensor, when installed on the roof of a factory, can also perform a monitoring function by forming radio picture(s) of the factory surroundings.
The type of radio map considered in this context is known in the English language by the name of PPI for "Plan Position Indicator". Devices of the type mentioned in the opening paragraph are known with which radio maps of the ground can be realised, such as for example, the radar called "Antilope" used on the French "Mirage 2000" fighters, and manufactured by the companies of ELECTRONIQUE SERGE DASSAULT and THOMSON-CSF. These known devices are pulse radars comprising a mobile aerial for realising the sector scanning necessary for establishing the map with polar co-ordinates. In this case a transceiver aerial is concerned whose support is constituted by a stabilized platform. To compensate for the stray pitching, rolling and twisting motion of the aircraft, the position of the stabilized platform is controlled such that this platform permanently rests in parallel with itself, in a predetermined direction. The disadvantages of this prior art device are its complexity, its fragility and its high cost, basically due to the two combined relative movements of the aerial.